Well, so far I've got a high score in the SMS version of Fantasy Zone of 61,400. I also started playing the arcade version on MAME, which seems a bit harder to me (surprisingly, since the SMS version is already quite hard) and got about 34,000 -- currently stuck at the second boss, who has more inner targets to hit than on the SMS version. Those scores are without using any kind of rapid fire... I'm sure rapid fire offers quite an advantage. But it's good to figure out the strategies of which weapons to buy. I'm not gonna bother with photographing the screen for my high score unless I get a really good score... anyone just starting out should be able to beat these in short order.
Here's a cheat for the Master System version. Wait through the attact mode until the storyline starts to scroll. Then rock your controller up and down at least 50 times (cheat sites list it as exactly 50, but I didn't really try to count, I just did it fast for a while). Then when you start the game, you'll be able to buy extra ships for 1000 a piece the first time you go to the shop. So I suggest waiting until after you beat the first boss when you have some real money saved up, and stock up on 9 extra lives (I think that's the most you can get).